1. Field of the Invention
The present invention relates to a polyester resin composition and a molded body, and more particularly to a polyester resin composition comprising a crystalline polyester and a specific organically modified layered silicate and to a molded body comprising the polyester resin composition.
2. Description of the Related Art
Crystalline polyesters are widely used as films or materials for molding because of excellent properties thereof, such as mechanical strength, heat resistance, weather resistance, and chemical resistance. Because compounding a reinforcing filler with such crystalline polyesters increases strength and heat resistance of the resin, the reinforced compositions thus obtained are advantageous as components for machinery parts. Examples of such reinforcing fillers include inorganic powders such as talc, glass fibers, and layered silicates. When such a powdered filler is used and a resin composition is obtained by melt kneading or the like, the filler has to be added at a high mixing ratio, which may affect the processability and dispersivity.
Accordingly, measures are taken to facilitate the peeling of layers in layered silicates and increase affinity thereof for resins by replacing exchangeable cations present between the layers of the layered silicate with organic onium ions. In particular, International Publication WO03/022927 discloses a method for obtaining a resin composition composed of a specific biodegradable polyester resin based on polylactic acid and an organically modified layered silicate in which ion exchange by a specific salt is performed at a ratio of 0.9 to 1.25 based on an ion exchange capacity of the layered silicate.
However, where an organically modified layered silicate with an ion exchange amount higher than 0.9 is added to a polyester, although heat resistance and rigidity are improved, impact resistance and resistance to hydrolysis may decrease.
Japanese Patent Laid-Open No. 2007-119729 discloses a method for increasing heat resistance and impact resistance in an amorphous state by compounding a methacrylic resin and an impact resistance enhancer with a polylactic acid and further adding an organically modified layered silicate and a reactive compound.